JPH0324610B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for automatically measuring the amount of load inside a bucket during loading of a bucket loader or the like.

To measure the load capacity of the bucket loader,
A system has already been developed that detects the lift cylinder oil pressure at the time of bucket lift-up and calculates the net cargo load inside the bucket through arithmetic processing by a microcomputer based on the detected oil pressure.

This system is effective for weighing when the bucket cart is at a high position, but when the bucket cart is at a low position near the ground, the amount of movement of the cargo due to the lifting of the bucket cart (tilt back) or vehicle acceleration This causes fluctuations in the oil pressure of the lift cylinder, making accurate weighing of the load extremely difficult. Therefore, accurate load weighing at the low position of the bucket is possible by completely stopping the vehicle, but in general loading operations, the vehicle is stopped after loading the cargo into the bucket, and the Waiting for the machine to come to a complete standstill before weighing the cargo will result in a significant drop in work efficiency. In addition, in the case of current load weighing, the center of gravity of the load is calibrated using calibration when installed on the actual machine.
When the position of the center of gravity differs from the position at the time of calibration due to cargo with different properties, an error will occur in the calculated value.

Also, JP-A-55-47421 and JP-A-56-
In the crane hanging load detection method of No. 161288, the hanging load on the crane is determined from the moment that the boom support device acts around the boom's pivot support point, and the moment that the boom's own weight acts around the boom's pivot support point. and the moment value after this reduction is calculated by dividing the moment value by the arm length of the moment that the hanging load acts around the pivot support point of the boom,
It is disclosed that the moment acting around the pivot point of the boom is detected based on the distortion of the piston rod of the luffing cylinder.

However, in the case of the above configuration, in order to detect the distortion of the piston rod, it is necessary to measure it at a certain high position or at a stationary position, as in the case of detecting the oil pressure of the lift cylinder described above. However, the above-mentioned drawbacks still cannot be overcome in traveling type loading machines such as bucket loaders.

This invention was made in view of the above circumstances, and its main purpose is to eliminate as much as possible the influence of the dynamic load on the bucket and its cargo, and to calculate it theoretically using measured values including the center position of the cargo load. ,
It is an object of the present invention to provide a highly reliable loading/unloading weight measuring device that can greatly improve the accuracy of weighing the cargo.

Another object of the present invention is to provide a cargo handling cargo load measuring device that can measure the cargo load in a bucket cart with high accuracy even while the vehicle is running, regardless of the height or low position of the bucket cart.

Another object of the present invention is to provide a loading/unloading weight measuring device that greatly contributes to improving the workability of bucket loading and work management.

In order to achieve the above object, the present invention provides a device for automatically measuring the amount of load inside a bucket in a traveling loading machine such as a bucket loader, and includes: In the groove formed in the direction of the hollow bucket hinge pin, in the groove formed in the circumferential direction along the inner peripheral surface of the hollow bucket hinge pin, or in the inner surface of the end of the vertical slit formed on the tip side of the lift arm. (b) a sensor for detecting the height position of the bucket; ) calculation means for calculating the amount of cargo load in the bucket by inputting signals from the sensor and the strain gauge; (d) automatically measuring the net load amount in the bucket based on the tensile strain and/or compressive strain; We are taking technical measures to do so.

This allows strain gauges to be installed in grooves or slits formed in these members to reduce strain in the bucket hinge pin, the bearing that receives the load, or the lift arm near the hinge pin with a simple structure and without bulk. Since the weight is detected, it is possible to accurately measure the weight without having to measure at a certain height of the bucket or being affected by dynamic loads.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

First, in FIG. 1, reference numeral 1 denotes a rotor bucket cart for cargo handling and loading, and its support mechanism 2 includes a lift arm 3 at which the bucket cart 1 is pivotally supported at its tip by a hinge pin P and is driven by a lift cylinder (not shown). It has a well-known configuration including a tilt linkage 4 for interlocking the bucket 1 with a tilt cylinder (not shown).

The hinge pin P is inserted through a pin hole at the tip of the lift arm 3 via a bearing 5, as shown in more detail in FIG.

An annular groove 6 having a semicircular arc cross section is provided on the outer periphery of the end of the bearing 5.

On the arcuate bottom surface of the annular groove 6, as shown in more detail in FIGS. 3 and 4, there are a plurality of strain gauges A1 arranged adjacent to each other at regular intervals in the width direction of the groove and also arranged at regular intervals in the circumferential direction of the groove. Each of B1 to A4 and B4 is pasted.

These strain gauges detect the amount of strain on the bearing 5 due to the weight of the bucket 1 and the amount of cargo inside the bucket.

That is, when the bucket 1 loads cargo, a shear force F acts on the end of the bearing 5 due to the total load W of the cargo load and the bucket's own weight, and this causes the annular groove 6 of the bearing to Stress is concentrated at the bottom of the arc.

Therefore, the strain gauge A in the groove 6
Tensile strain occurs in the array areas of strain gauges B1 to A4, and compressive strain occurs in the array areas of strain gauges B1 to B4. The respective strain gauges A1 to A4 and B1 to B4 detect the amount of strain.

These strain gauges are A/D as shown in Figure 5.
The detected value signal is transmitted to cargo handling weight calculation means 8 via the converter 7.

Further, the means 8 also receives a signal from a sensor 9 for detecting the height of the hinge pin P. The sensor 9 is configured to measure the height of the hinge pin by detecting the stroke of the lift cylinder or the rotation angle around the attachment pin of the lift arm 3 to the vehicle body. That is, since the hinge pin P rotates in a constant trajectory by the link mechanism that holds the bucket, it is possible to convert the height of the hinge pin P by detecting the stroke of the lift cylinder or the rotation angle of the hinge pin P. can.

The calculation means 8 includes a ROM 10 and an output device 11.
It consists of a microcomputer equipped with

The calculation formula for the total load W and other necessary data are stored in the ROM 10 in advance.

That is, when the bucket 1 is fully pulled up after loading as shown in FIG. 1, the total load W of the bucket's own weight and the cargo load is held by the hinge pin P and the tilt linkage 4.

Therefore, in FIG. 1, the relationship between F, F ₁ and W is expressed by the following equation. That is, the weight W of the bucket 1 and the cargo consists of a load F on the hinge pin and a load F ₁ on the tilt linkage 4. here,
(F... combined load, F ₁ ... load applied to tilt linkage 4, W... total load mentioned above, L ₁ ... distance between bucket hinge pin P and bucket load center,
L ₂ ...the hinge pin P and the tilt linkage 4
distance, α, β, θ... angle).

F ₁・L ₂ = W・L ₁ , F=F+W W=F・cos(β−θ)−F ₁ cos(β−α) F ₁ =Fsin(β−θ)/sin(β−α) ∴ =F[cos(β-θ) −cos(β-α)sin(β-θ)/sin(β-α)]
...(1) Moreover, the total load W can also be determined by the following formula.

W=√ ² + ² ₁ −2・₁ (−)……(2) θ−α=(β−α)−γ γ=cos ⁻¹ F ₁ /Fsin(180+α−β) Therefore, ROM10 has Either of the above arithmetic expressions (1) or (2) is stored.

In the case of formula (1), the α angle and β angle are uniquely determined by the height of the hinge pin P, and as mentioned above, the height is determined by the stroke of the lift cylinder or the area around the pin where the lift arm 3 is attached to the vehicle body. It can be measured by the rotation angle of Therefore, by measuring the value of the composite load F, its acting direction (θ angle), and the height of the bucket hinge pin P, the total load W can be determined.

The F value and θ angle in this case can be determined from the results of strain measurement using the strain gauges A1, B1 to A4, and B4 described above.

In other words, since the distribution of the shearing force acting on the end of the bearing 5 due to the composite load F is constant as shown in FIG. 4, the shearing force is generated at the bottom of the annular groove 6 at the end of the bearing Tensile strain and compressive strain are measured by adjacent strain gauges A1 and B.
If measured by each of 1 to A4 and B4,
The F value and the θ angle can be determined from the measurement results.

On the other hand, in the case of formula (2), tilt linkage 4
The load F ₁ (obtained by installing a strong gauge on the tilt linkage or measuring the oil pressure of the tilt cylinder), the combined load F acting on the bucket hinge pin P, and the height of the hinge pin (height is determined by installing a strong gauge on the tilt linkage or measuring the oil pressure of the tilt cylinder), the combined load F acting on the bucket hinge pin P, and the height of the hinge pin The total load W can be determined by measuring the total load W (uniquely determined by the stroke or the rotation angle of the lift arm).

Thus, the strain gauges A1, B1 to A4,
The calculation means 8 inputs the signals from B4, _F1 and the bucket hinge pin height detection sensor 9.
The calculation formula (1) or (2) is called from the ROM 10, and calculation processing is performed based on the called formula to calculate the total load W. At the same time, the weight of the bucket 1 is calculated by subtracting the weight of the bucket 1 from the total load W. Calculate the net load amount within. Device 1 outputs the resulting signal
1, the device displays and records the load amount.

Therefore, the output device 11 in the illustrated example consists of a digital display 11A and a printer 11B.

In the embodiments shown in FIGS. 6 and 7, a hollow bucket hinge pin P' is used, and an annular inner groove 6' having a semicircular arc cross section is provided on the inner peripheral surface of the hinge pin, and a strain gauge A1 is provided at the bottom of the groove. B1 to A6 and B6 are attached.

In this case, the annular inner groove 6' is formed along the cross section of the hollow hinge pin P which receives shearing force between the boss part of the bracket 1' which is integral with the bucket cart 1 and the boss part of the lift arm 3. Formed on the peripheral surface.

On the other hand, each strain gauge A1, B1 to A6, B
6 are attached in substantially the same arrangement as in the previous embodiment.

In the case of this embodiment, when the shearing force shown by arrow F/2 in FIG. Since compressive strain occurs in the bonded portions of the adjacent strain gauges A1 and B4, these strains are detected by each of the strain gauges B1 and A4 and A1 and B4, respectively.

By inputting and arithmetic processing these detection value signals to the calculation means 8 in FIG. 5, the net load amount in the bucket bag 1 is calculated, and its display and recording are performed as in the previous embodiment. be done.

In yet another embodiment shown in FIGS. 8 to 10,
Strain in the lift arm 3 is detected.

In this case, a slit 12 is provided on the tip side of the lift arm 3 near the hinge pin P and has a semicircular arc shape at the upper and lower ends, and a plurality of strain gauges A, B, C is pasted at regular intervals.

In this way, a shearing force is applied to the lift arm 3 along the longitudinal direction of the slit 12 (arrow F/ in FIG. 9).
2), strain gauge A absorbs the compressive strain that occurs in that area, and strain gauge C
detects the tensile strain occurring in that part.

Furthermore, when a compressive force (arrow F'/2 in FIG. 9) is applied in the width direction of the slit 12, or when a tensile force is applied in the opposite direction to the compressive force, each strain gauge A, B, In the former case, compressive strain occurs in all parts of C, and in the latter case, tensile strain occurs, so each strain gauge detects the strain in either case in a composite state.

Therefore, by inputting the detection signals from each strain gauge A, B, and C to the calculation means 8, the net load amount in the bucket bag 1 can be automatically measured as in the previous embodiment, and its display and recording can also be performed. It can be carried out.

In the above-mentioned embodiment, it is also possible to calculate the total weight loaded onto a transporter such as a dump truck by the bucket loader, the amount of unloaded material remaining, etc.

In this case, the maximum load amount of the transporter is stored in advance in the internal memory provided in the calculation means 8 shown in FIG. 5, and the calculation means 8 calculates the net load amount in the bucket 1 as described above. At the same time, by comparing the calculated weight value with the maximum loading capacity,
What is necessary is to calculate the total loaded weight or remaining loaded amount for the transporter at that time. If the calculated total loaded weight or remaining loaded amount is digitally displayed on the display 11A using the output signal from the calculation means 8, the loader operator can instantly and accurately check the loading and unloading status of the cargo into the transporter. I can understand it.

The indicator 11A also has a lamp 11a that lights up or blinks when the cargo in the bucket 1 is overloaded with respect to the transporter, and a lamp 11a that lights up when the cargo is properly loaded, depending on the input signal from the calculation means 8. If the lamp 11b that flashes and the lamp 11c that lights or flashes when there is still insufficient loading are provided in different colors, overloading of the transporter can be prevented by the display of these lamps.

Reference numeral 13 in FIG. 5 is a large external display that is installed outside the loader and displays the loaded weight digitally based on the signal from the calculating means 8. It can be easily confirmed even from

Reference numeral 14 in the figure is external input means such as a keyboard connected to the input section of the calculation means 8 via an interface. By this means, various data such as the vehicle identification number, maximum loading capacity, driver code number, customer name, cargo handling product name, specific gravity and moisture content of the cargo handling machine, such as the vehicle identification number of a dump truck, can be set and programmed, and the program can be controlled. Necessary data can be retrieved and printed out during cargo handling work or when the work is completed.

As described above, in the present invention, the strain occurring in the lift arm at or near the hinge part of the bucket cart due to its own weight and the amount of cargo is detected,
Since the net cargo load in the bucket is automatically measured based on the strain, the cargo load can be accurately measured with almost no influence from the dynamic load of the bucket or the cargo in the bucket.

In addition, the strain gauge has bucket hinge pins,
Since it is installed in a groove or slit formed in the bearing or parts of the lift arm near the hinge pin that receive it, it has a simple configuration and is not bulky, so detection can be performed without being subjected to external shocks and is reliable. is high.

For this reason, the height and low position of the bucket and the running and
The bucket load can be measured with high precision without having to stop, etc., and greatly contributes to increasing the efficiency of bucket loading work and improving work management.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of a bucket device illustrated for explaining the present invention, Fig. 2 is an enlarged sectional view of the hinge pin portion of the device, and Fig. 3 is an A of Fig.
FIG. 4 is a sectional view taken along the - line in FIG. 2, FIG. 5 is a block diagram of an automatic bucket load measuring system, and FIG. 6 is a bucket hinge pin boss section according to another embodiment of the present invention. 7 is a sectional view taken along the line - in FIG. 6, FIG. 8 is a partial side view of a bucket lift arm according to yet another embodiment of the present invention, and FIG. 9 is a sectional view taken along the line - in FIG. FIG. 10 is an enlarged view of part B of FIG. 1 is a bucket, 3 is a lift arm, P is a bucket hinge pin, A1, B1 to A6, B6, A to C
9 is a strain gauge, 9 is a bucket height detection sensor, and 8 is a calculation means.

Claims (1)

[Scope of Claims] 1. A device for automatically measuring the load amount in a bucket in a traveling loading machine such as a bucket loader, which includes a groove formed in a circumferential direction along the outer periphery of a bearing into which a bucket hinge pin is fitted. The bucket hinge pin is hollow and is installed at predetermined intervals either in a groove formed in the circumferential direction along its inner circumferential surface, or on the inner surface of the end of a vertically long slit formed on the tip side of the lift arm. a strain gauge that detects the tensile strain and compressive strain of the bearing, the hollow bucket hinge pin, or the lift arm; a sensor that detects the height position of the bucket; and a sensor that inputs signals from the sensor and the strain gauge. 1. A loaded weight measuring device comprising: calculation means for calculating the amount of loaded load in the bucket bag based on the tensile strain and/or compressive strain, and automatically measures the net load amount in the bucket bag based on the tensile strain and/or compressive strain. 2. The groove formed in the circumferential direction along the outer periphery of the bearing into which the bucket hinge pin is externally fitted, and the groove formed in the circumferential direction along the inner peripheral surface of the hollow bucket hinge pin are each annular grooves. 2. The loaded weight measuring device according to claim 1, wherein the cross section has a semicircular arc shape. 3. The loaded weight measuring device according to claim 1, wherein the vertically elongated slit formed at the tip end of the lift arm is a slit whose upper and lower ends are semicircular arc surfaces. 4. Claim 1, characterized in that the sensor that detects the height position of the bucket cart is a sensor that detects the stroke of a lift cylinder for driving the bucket cart up and down or the rotation angle of the lift arm around the hinge pin. Loaded weight measuring device as described. 5. The loaded weight measuring device according to claim 1, wherein the calculation means includes an output device for displaying and recording the calculated value of the net weight of the loaded bucket.